Saturn MLV
Successive Saturn Modified Launch Vehicle studies as part of the Apollo Applications Program proposed a dazzling array of Saturn derived concepts, intended to deliver uprated heavy launch vehicles based on existing hardware.
Constrained mainly by the height of the VAB and launch infrastructure, Saturn MLV features upgraded F1A engines, stretched fuel tanks and improved upper stage engines such as the J-2T or a hypothetical "Advanced Engine." Meanwhile, Saturn ELV is the result of a NASA in-house study given no height restrictions.
Other designs including the Saturn V/4-260, which works around load bearing challenges by adding liquid fuel tanks on top of massive AJ-260X solid rocket boosters. An alternate approach employed by the Saturn V-23(L) uses strap on liquid rocket boosters with 2x F1A engines each.
The naming conventions from the various MLV studies can be confusing so they have been slightly simplified for the purpose of this guide.
| Variant | First | Second | Third | Boosters | Comments |
|---|---|---|---|---|---|
| MLV-V-1 | MS-IC-1 | MS-II-1; 5xJ2 or J-2T | S-IVB | J-2T allows short S-II interstage | |
| MLV-V-1A | MS-IC-1; 6xF1 | MS-II-2; 7xJ2 | MS-IVB | ||
| MLV-V-2 | MS-IC-1 | MS-II-1 | MS-IVB; 1xRL-20 | ||
| MLV-V-3 | MS-IC-1 | MS-II-2 | MS-IVB; 1xRL-20 | ||
| MLV-V-3B | MS-IC-1 | MS-II-2; 4-7xRL20 | MS-IVB; 1xRL-20 or J-2T | Uprated S-IC with INT-17 on top | |
| MLV-V-4(S) | S-IC | S-II | S-IVB | 4x UA-1205 | |
| MLV-V-4(S)A | MS-IC-4 | MS-II-1 | MS-IVB | 4x UA-1205 | |
| MLV-V-4(S)B | MS-IC-4 | S-II | S-IVB | 4x UA-1207 | V-22(S) with stretched tanks & adv engines dropped after Phase 1 study |
| MLV-V-23(L) | MS-IC-1; 5xF1 | S-II | MS-IVB | 25x4m (KSP Scale) LRB; 2x F1 | 24(L) with adv engines dropped after Phase 1 study |
| MLV-V-25(S) | MS-IC-25 | S-II | MS-IVB | 4x UA-1207 | |
| ELV | MS-IC-4 | MS-II-1; 7xJ2 | MS-IVB | 4x UA-1207 | NASA no size limit study |
| V/4-260 | S-IC | MS-II-2 | 4x AJ-260X with addt'l fuel tanks | Boeing study |
The source docs refer to "Advanced Upper Stage Engines", often considered to be a reference to the conceptual HG-3, which was never developed. The RL20-P3 is used as a drop in replacement here.
The fins on the S-IC stage provided aerodynamic stability in the event of a main engine failure to support a successful abort with the Launch Escape System. Although many of the source doc images shows fins, it is likely that they would have been omitted from all post-Apollo Saturn builds to save weight.
The proposed length of fuel tanks varied a fair amount as studies matured over the years. The tank extensions have been rationalised, rescaled to KSP scale and rounded to the nearest available size in BDB to create a set of baseline "building blocks" for the MLV rocket builds.
| Baseline Stage | B9 Tank Extension | Engine Number & Type |
|---|---|---|
| S-V | Centaur D | 2x RL-10 |
| S-IVB | 1x J2 | |
| MS-IVB | 3m | 1x J2 |
| S-II | 5x J2 | |
| MS-II-1 | 1.5m | 5x J2 |
| MS-II-2 | 3m | 5x J2 |
| S-IC | 5x F1 | |
| MS-IC-1 | 3m | 5x F1A |
| MS-IC-4 | 6m | 5x F1 |
| MS-IC-25 | 9m | 5x F1 |
Kerbal Koncepts: Saturn V ELV with an S-V fourth stage